Apparatus for bleaching wood pulp



Aug. 16

F. G. SHERBONDY ET AL APPARATUS FOR BLEACHING WOOD PULP Fi led March e. 1926 2 Sheets-Sheet l 550mg 6f. 67/525 o/var,

Max 505/014,

' 1,638,965 1 1927 F. G. SHERBONDY ET AL APPARATUS FOR BLEACHING WOOD PULP Filed March a. 1926 2 Sheets-SheetZ Patented Aug. 16, 1927.

UNITED STATES PATENT OFFICE.

FREDERICK G. SHEBBONDY, OF AKRON, OHIO, AND MAX E. BOEHM, 0F APPLE'ION,

WISCONSIN.

APPARATUS FOR BLEACHING WOOD PULP.

Application filed March 6, 1926. Serial No. 92,867.

This invention relates to apparatus for bleaching pulp or the like, andthis application is a continuation in part of our co-pending application Serial No. 10,811, filed February 21, 1925.

An object of the invention is to produce an apparatus for bleaching pulp under pressure, without heat, and at high consistency.

Another object of the invention 15 to produce an apparatus for bleaching pulp wherein the pulp is thoroughly agitated and mixed during the bleaching process with a minimum expenditure of time and power.

The objects of our invention are realized in an apparatus comprising a rotatable. a1rtight retort or chamber for receiving the mixture of pulp and bleaching liquor, means for subjecting the mixture to pressure, and specially constructed battles mounted within the chamber to effectively and efficiently agitate the mixture during the bleaching process.

By our method of cold bleaching, under pressure, a tougher and more durable prodnet is obtained than is possible in a process of hot bleaching, which tends to weaken the fibres of the stock. Also, by practicing the bleaching process under pressure, better penetration of the stock by the liquor is obtained.

Another advantage of our method of bleaching in an air-tight container is that the escape of chlorine gas is prevented, thereby economizing in the cost of practicing the method.

The invention is shown in the accompanying drawing in which:

Fig. 1 is a side elevation of the apparatus:

Fig. 2 is a view taken along line 22 of Fig. 1 showing the relative positions of the baflie plates in the chamber;

Fig. 3 is a view taken along line 3-3 of Fig. 2. showing the manner in which the battle plates are mounted;

Fig. 4 shows the details of supporting and bracing the batiie plates; and

Fig. 5 is a view of Fig. 4 taken from the direction indicated by arrow of Fig. 4.

Referring to the drawing, 1 indicates the bleaching chamber or retort in the form of a spherical globe provided with trunnions 2, i at diametrically opposite points. The chamber is-mounted for rotation about the axis of .the trunnions by seating the trunnions in bearings at the top of pillars or supports 3, .3. Rotation of'the chamberis effected by means of gear 4: mounted upon one of the truimions and connected through reduction gearing (not shown) to any suitable source of power. At a point equi-distant from the two trunnions, a man-hole 5 is formed in the chamberand is provided with a cover 6 which, when clamped over the man-hole, forms an air-tight and pressure tight closure. The chamber is also rovided with an outlet valve 7, located at a point opposite the man-hole 5.

Each trunnion 2, is provided with a pipe 8, concentric with the axis of rotation, and communicating with the interior of the chamber.

A series of batlleplates 9, 9', 10 and 10, are secured to the inner wall of chamber 1 and serve as mixing or agitating blades when the chamber is rotated. As will be seen from Figs. 3, 4 and 5 these bathe plates are of V-shape, with the point of the V of adjacent plates pointing in opposite directions.

Referring to Fig. 2, baflles 10 and 10" point in the direction of rotation, as indicated by arrows 11, and baflies 9 and 9 pointv away from the direction of rotation. The point or apex of each baflle, that is, the line of intersection of the two wings of each bafile, is located along a straight line extending through the center of the chamber. Fig. 4 is a view of baffle 9' as Viewed from the center of the chamber. As will be seen the plane of each wing or side ofthe battle passes through the center of the globe, and while this is the preferred construction, it is to be understood that it is not absolutely essential that the planes of the wings pass through the center. The sides or wings of the battles may be made of separate plates or the two may be formed from a single sheet. Referring to Fig. 5, it, will be seen that the bottom edge of each wing conforms generally to the inner wall of the globe, but elongated notches 12 and 12' are formed in the lower edge of each bafile for .a purpose which will appear hereinafter. A series of channel bars 13 are secured to the trailing side of the wing of each battle for the purpose of giving rigidity and strength to the plates. These channel bars preferably extend at rightangles to the wall of the globe, their axes extending through the center of the globe. The bafiles are secured to the wall of the globe by a series of webbed angle irons 14, which are secured on one side to the wall and on the other to the channel bars 13. The outer, narrow ends of the bullies are not provided with channel bars, but depend for their support upon an angleiron only, as will be seen from Figs. 3, 1-, and 5.

The operation or the apparatus is as follows: A quantity of pulp and bleaching liquor is admitted to the globe which is then scale-cl tightly against the escape of gases, The globe is then rotated at the desired speed. for properly mixing and agitab ing the mixture. l ve may rely upon the cares formed during the process of bleaching to develop a pressure within the globe to assist in getting good penetration of the liquor into the stock, or we may create a pressure Within the globe by introducing air, steam, or any other suitable fluid through pipes 8 at the desired pressure.

The rotation of the globe tends to raise the pulp on the Lip-turning side of the chamer and to cause it to flow back towards the lowermost point of the globe. This causes the pulp to move continl'iously in a rolling or tumbling flow in the same direction, which is ell'ective in causing a thorough mixing of the stoclrand liquor. The baiiles assist in raising the stock from the bottom of the globe, but in addition, they are so arranged as to cause alternate concentrating and spreading of the flow. Referring to Figs 3 and it will be seen that when ba'lile 9 is moving in the direction of arrow 11, it will carry a portion oiithc mixture along in frontof it, and itocgins its upward travel the sid of the baffle form a PGClKEE'illlEQ element and direct the flow towards the point or the haille where it will pass over the upper edge in a concentrated stream. But with respect to baiilc 10, the sides will act as deflectors for the stream and will cause the stock to spreao out and pass over the upper edge of the bafllc in a more or evenly distributed manner. It will be noted that since adjacent baillcs are rcvci'scd. will: respect to each other the ilow of the mixture is si'abjccted to alternate concentration and dispersion.

1y using the particular type of container and the specially shaped bullies, We are able to thoroughly mix and bleach a given amount of pulp in less time and with less power than with other lznown types of bleaching machines.

The slots or notches l2. 1% formed in the bottom edge of the ba es are construction details to accoi'nmorlate the bullies to seams and rivets or other fastening means in consl routing; the. lohe container. but these openings also rvc for the purpose of allowing the ox aching fluids to drain from the pockets toimed by the bailles when the maessons ported for rotation about a diametral axis,

means for subjecting the chamber to pressure, and agitating blades secured to the inner Wall of the chamber, adjacent blades being formed to present convex and concave surfaces respectively to the pul and in to operation with the spherical s' ape of the container to produce alternate spreading and concentration flow of the material under treatment, as the spherical chamber is rotated.

2. Apparatus for bleaching pulp comprising a gas-tight spherical chamber for receiving a mixture of pulp and bleaching liquor, means for creating a pressure within the chamber, means for rotating the chamber about a diametral axis, and agitating blades-secured to the inner Wall of the charm her, adjacent blades being formed to present convex and concave surfaces respectively to the pulp to produce alternate spreading and concentrating flow of the mixture as the chamber is rotated.

3. In apparatus of the kind described, the combination. of a spherical rotary chamber, alternate convex and concave bathe plates arranged within the chamber and at substantially right-angles to the Wall thereof, a plurality of channel bars secured to the trailing side of each battle plate, and a pinrality of angleirons secured to said channel bars and to the wall of said chamber for holding the bafile plates in position.

4. Apparatus for treating pulp or the like 7 comprising a spherical chamber, means for rotating the chamber, two series of similarly s .apcd ballles each composed of a pair of plates angularly disposed to each other secured to the inner Wall of the chamber, one series being positioned in opposite direction to the other series with respect to the direction or rotation Wherehv the flow is subjected to alternate. spreading and conccntratwhereby as the chamber rotates the material" is caused to flow in athin sheet over the inner edges of the plates.

6. In apparatus for treating semifluid material a spherical chamber mounted for rotation about a diametral axis, an agitating bafile mounted upon the inner surface of the chamber for spreading the material, a, concentrating baffle mounted upon said surface in position to receive the material after sgreading, and comiosed of convergent 10 P ates forming a poo et for concentrating the material .an pouring t e material in a concentrated stream over the inner edges of the plates et their junction.

- FREDERICK G. SHERBONDY.

AX E. BQEHM.

In witness whereof we attest oursigna I tures. 

